There are a couple of other topics which appear to describe this vase but the images have gone from them (Tinypic and Webshots) so I am adding this for future reference so we have copies on the board.
Found it today and it is now my 3rd piece of Maltese glass! (2 x Mtarfa and 1 x Mdina)
Dimensions: 18 cm tall, 12.5 cm wide, 4 cm deep (all dimensions to widest point)
Signed: Mdina (no date)